Data…
Please check the data repositories associated with each study. If you are unable to find what you need, then contact Ian. We are happy to share our data for academic purposes, but the size of our datasets makes hosting them online impractical.
Code…
We often develop R code for performing landscape genetic and related analyses. Any of our published code can be found here.
Multiple Matrix Regression with Randomization (R function: MMRR)
MMRR presents a method for quantifying and disentangling the relative effects of isolation by distance (IBD) and isolation by environment (IBE). In practice, this method can easily be extended to quantify the relationships between any number of explanatory variables that can be represented as distance matrices and a given response variable (e.g. genetic distances).
R code and a brief tutorial: MMRR tutorial
Dryad entry: MMRR function R script
Reference to be cited: Wang I. J. 2013. Examining the full effects of landscape heterogeneity on spatial genetic variation: a multiple matrix regression approach for quantifying geographic and ecological isolation. Evolution, 67: 3403-3411. [pdf]
Calculating topographic paths and distances (R package: topoDistance)
The topoDistance package provides tools for finding shortest topographic paths and topographic least cost paths in R.
Topographic distances are calculated by weighting the edges of a landscape graph by the hypotenuse of the horizontal and vertical distances between raster cells and then finding the shortest total path between nodes of interest. The package also includes tools for mapping topographic paths and plotting elevation profiles.
topoDistance is available on CRAN: https://CRAN.R-project.org/package=topoDistance and can be installed using install.packages(“topoDistance”)
You can also install topoDistance from its GitHub repository using devtools::install_github(“ianjwang/topoDistance”)
You can download the user manual for topoDistance by clicking here.
You can also view the topoDistance vignette for help getting started.
Reference to be cited: Wang I.J. (2020) Topographic path analysis for modeling dispersal and functional connectivity: calculating topographic distances using the topoDistance R package. Methods in Ecology and Evolution, 11: 265-272.
